Decreased expression of ZO-1 is associated with tumor metastases in liver cancer.

Certain types of cancer exhibit downregulated expression of zonula occludens-1 (ZO-1), which serves an important function in tumor progression; however, the underlying molecular mechanisms that lead to this downregulation in cancer remain unclear. In the present study, the expression of ZO-1 in liver cancer (LC) tissues was investigated. Western blot and reverse transcription-quantitative polymerase chain reaction assays were used to detect the expression of ZO-1 protein and mRNA in LC tissues and paired adjacent non-tumorous tissues. The results indicated that, compared with non-tumorous tissues, the expression of ZO-1 was significantly downregulated at the protein (P<0.001) and mRNA (P=0.006) levels in LC tissue samples. In addition, various cellular and molecular methods were applied, including MTT, colony formation, flow cytometry and Transwell assays. The results indicated that overexpression of ZO-1 inhibited cell viability, proliferation and migration, and induced G0/G1 phase arrest in vitro.